3 Things We Learned from New Hampshire

Trump and Sanders cruise to big wins while Rubio and Clinton stumble.

Presidential hopefuls Bernie Sanders and Donald Trump celebrated runaway victories Tuesday night, providing further proof that a primary pitting outsiders against establishment is a long way from over.

Mr. Trump, the blustery New York businessman, took advantage of a fragmented Republican field to secure 35 percent of the vote and win the state by 19 points. Sen. Sanders (I-Vt.), a self-described Democratic-Socialist, cruised to a 22-point win over Hillary Clinton, the second-largest margin of victory in the history of the New Hampshire Democratic primary.

“I was surprised at the margin of Clinton’s defeat,” Dr. Cornfield said. “I expected her to lose [last night], but I didn’t expect her to lose this badly. According to exit polls, she lost the women’s vote, she lost the moderate vote, she lost in every county in the state. And she lost to someone who’s not even nominally a Democrat. It was a beating.”

“He knows, as does [Ms. Clinton], that winning African Americans and Hispanic Americans is going to be crucial in the weeks ahead,” Dr. Cornfield said.

He still sees a clearer path for Ms. Clinton, provided she emphasizes the right points. Her recent trip to Flint, Mich., was a good start, Dr. Cornfield said.

“That and negotiating and scheduling a debate in Flint two days before the Michigan primary are both good moves,” he said. “She has to make Flint and repairing Flint the centerpiece of her campaign. Infrastructure investment is a great issue for her. It speaks to her skills, her passion and, in this case in Flint, it speaks to helping children. This is tailor-made for her.”

Trump is evolving

This would have seemed unfathomable seven months ago, when Mr. Trump rode down an escalator and announced his candidacy in a winding, rant-filled 45-minute speech. But he has emerged as a viable candidate, Dr. Cornfield said, and he is changing his tone.

“He is starting to mix in some positive messages along with his branded anger-and-insult approach to campaigning,” Dr. Cornfield said. “He uses the word ‘love’ a lot. He talked about drug addiction in New Hampshire. He’s still angry, but he’s started to shift.”

Mr. Trump became the 10th non-incumbent Republican candidate to win at least 20 percent of the vote in both Iowa and New Hampshire since 1980, according to FiveThirtyEight. Four of the previous nine went on to secure the nomination, and three others—George H.W. Bush in 1980, Bob Dole in 1988 and Mitt Romney in 2008—performed well enough to position themselves for future nominations. That does not guarantee anything, Dr. Cornfield said. But the GOP can no longer treat Mr. Trump as a fad.

“The question for him is can he get beyond that 25-30 percent number as other candidates fall out,” Dr. Cornfield said. “That’s where it gets really complicated.”

The GOP establishment is in flux

The fragmented middle of the Republican primary includes former Florida Gov. Jeb Bush, Ohio Gov. John Kasich and Sen. Marco Rubio (Fla.). New Jersey Gov. Chris Christie suspended his campaign Wednesday. That quartet split more than 29 percent of the vote in Iowa and more than 44 percent of the vote in New Hampshire.

“So much of politics boils down to arithmetic, and this is where the Republican party has a collective-action problem,” Dr. Cornfield said. “If they all stay in, they all split the anti-Trump vote. Meanwhile, Ted Cruz continues to pull his 20 percent, and he shows no signs of weakening as we go to the Southern states.”

At some point, the Bush-Kasich-Rubio logjam will reduce down to a single candidate, he said. It remains unclear who that candidate will be. Mr. Kasich finished second in New Hampshire and is hoping a boost in fundraising can get him to March and the Michigan, Illinois, Missouri and Ohio primaries, according to the Los Angeles Times. Mr. Rubio, who emerged in Iowa with a strong third-place finish, wilted at Saturday’s GOP debate, Dr. Cornfield said. That opened the door for Mr. Bush to crack double-digits in New Hampshire.

It may have saved Mr. Bush’s campaign, Dr. Cornfield said.

“Everybody thinks that—the donors, the party insiders, everybody,” he said. “Now, suddenly, Jeb Bush seems to have a chance. And of course he has more money than any of them. How is it going to play out? I can’t wait to find out.”